C
Well, it takes a long time before you can get a publishing company to publish you, so most preachers and Theologians have to self-publish. Not many of them have anywhere near all the money some on here claim they do, so the typing, consolidation and proofing is often handled by family and friends. That is seldom a really "professional" group. They don't deliberately set out to publish books with grammatical errors and typos, but it happen more than you might think.
My brother translates christian English/American books to Dutch, but that's with a publisher. It's all quite cheap those christian books, they often have translators who do it for free, but there's always someone who checks it all LOL and then they change the title into something directly translated from English, which is wrong in Dutch and he gets so annoyed, but they pay and it's their book.